Continuous flow preparation method of 2,6-diethyl-4-methylaniline diazonium salt

Abstract

The invention discloses a continuous flow preparation method of 2,6-diethyl-4-methylaniline diazonium salt. The method comprises the steps: adding a diazotization reagent, an acid and 2,6-diethyl-4-methylaniline to an integrated reactor material feeding mouth continuously, and performing a diazotization reaction so as to obtain the 2,6-diethyl-4-methylaniline diazonium salt continuously in an integrated reactor material discharge mouth for subsequent reactions. The production process is safe and efficient, no accumulation of high-risk diazonium salt is caused, and the problem of large viscosity of a kettle reaction system is solved; and the product has high yield and purity, and the process has simple and efficient operation.

Description

technical field [0001] The invention relates to a preparation method of a pesticide intermediate, more particularly to a continuous flow preparation method of 2,6-diethyl-4-methylaniline diazonium salt. Background technique [0002] 2,6-Diethyl-4-methylaniline diazonium salt is a key intermediate of the herbicide pinoxaden. [0003] CN109134187A, CN106928253A, CN102395546A, CN108864144A all report that 2,6-diethyl-4-methylaniline is first prepared 2,6-diethyl-4-methylaniline diazonium salt by kettle reaction, and then Its bromination method prepares 2,6-diethyl-4-methylbromobenzene. [0004] These methods have the following significant disadvantages: [0005] (1) The kettle reaction for the preparation of diazonium salts has great potential safety hazards, which limits the increase in production capacity. After the diazotization reaction, there will be a large amount of diazonium salts in the reactor. Since the diazonium salts are easy to decompose and cause explosions, t...

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Problems solved by technology

[0005] (1) The kettle reaction for the preparation of diazonium salts has great potential safety hazards, which limits the increase in production capacity

After the diazotization reaction, there will be a large amount of diazonium salts in the reactor. Since the diazonium salts are easy to decompose and cause explosions, there are great safety hazards in the industrial production process, thus limiting the use of 2,6-diethyl-4 -Increased production capacity of methylaniline diazonium salt

[0006] (2) In the kettle reaction, the diazonium salt gradually increases, and the viscosity of the system gradually increases, which increases energy consumption and limits the increase in production capacity of 2,6-diethyl-4-methylaniline diazonium salt

[0007] (3) Large energy consumption and high production cost

In order to ensure safe production, the preparation of diazonium salt needs to be carried out at low temperature (-5°C), which increases energy consumption

[0008] (4) Due to the lower temperature during the preparation of the diazonium salt, the follow-up bromination reaction needs to be carried out as soon as possible after the diazonium salt is prepared, so the lower temperature of the diazonium salt will require a higher temperature during the follow-up bromination, resulting in energy consumption Big

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